1. Field of the Invention
The present invention relates to a high-frequency module and a method for manufacturing the same.
2. Related Background Art
In high-frequency modules primarily used for mobile communication equipment such as portable telephones, a high-frequency circuit including a high-frequency semiconductor element and a peripheral circuit is formed on a substrate, and a metal cap often is disposed so as to cover a surface of the substrate on which the high-frequency circuit is disposed, in order to protect the high-frequency semiconductor element and shield it from electromagnetic waves. In ordinary conventional high-frequency modules, a high-frequency semiconductor element 102 and electronic components 103 such as chip resistors and chip capacitors are mounted on a substrate 101, and electrically connected to each other by thin metallic wires 104 or a wiring pattern (not shown in detail), thus forming a high-frequency circuit, as shown in FIG. 12. A metal cap 120 is fitted onto the substrate 101 or soldered thereto.
In the conventional high-frequency module shown in FIG. 12, however, the metal cap 120 has made it difficult to reduce the package height. When the metal cap 120 is made thinner, the strength of the metal cap 120 cannot be maintained, and thus, the metal cap becomes pliable so that it may come in contact with the high-frequency circuit. In order to avoid a short-circuit due to contact between the metal cap 120 and the high-frequency circuit, it is also necessary to provide a clearance below the metal cap 120 in view of the pliability of the metal cap 120. In an example, it was necessary to set the thickness of the metal cap 120 to about 100 μm, and set the clearance provided below the metal cap 120 to about 80 μm If this total thickness of about 0.2 mm could be reduced, then the height of the high-frequency module could be reduced further.